Console plug-and-play layer: always-on, BPM autostart, game launchers

- Mask all suspend paths + dconf no-sleep/no-lock defaults (local + GDM):
  the console must stay reachable over SSH/RDP at all times
- Autostart Steam Big Picture Mode for the kid account only
- Enable tailscaled (idle until 'tailscale up')
- First-boot flatpaks: ProtonUp-Qt, Heroic, RetroDECK

Already in the bazzite base, so not added: Steam, Tailscale, automatic
updates (uupd.timer), Firefox via first-boot flatpak manager.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

files/console/etc/dconf/db/gdm.d/50-bc250-nosuspend

@@ -0,0 +1,6 @@
+# Keep the login screen from trying to suspend the console while nobody
+# is logged in (suspend is also hard-blocked by masking sleep.target).
+
+[org/gnome/settings-daemon/plugins/power]
+sleep-inactive-ac-type='nothing'
+sleep-inactive-battery-type='nothing'